Bioprocess and Biosystems Engineering最新文献

The ubiquitous presence of pharmaceuticals and personal care products (PPCPs) in the environment has become a significant concern due to their persistence, bioaccumulation potential in biota, and diverse implications for human health and wildlife. This review provides an overview of the current state-of-the-art in environmental bioremediation techniques for reducing pharmaceutical residues, with a special emphasis on microbial physiological aspects. Numerous microorganisms, including algae, bacteria or fungi, can biodegrade various pharmaceutical compounds such as antibiotics, analgesics and beta-blockers. Some microorganisms are capable of transferring electrons within the cell, and this feature can be harnessed using Bio Electrochemical Systems (BES) to potentiate the degradation of pharmaceuticals present in wastewater. Moreover, researchers are evaluating the genetic modification of microbial strains to improve their degradation capacity and expand list of target compounds. This includes also discuss how environment changes, such as fluctuations in temperature or pH, may affect bioremediation efficiency. Furthermore, the presence of pharmaceuticals in the environment is emphasised as a major public health issue because it increases the chance for antibiotic-resistant bacteria emerging. This review combines existing information and outlines needed research areas for improving bioremediation technologies in the future.

Protein engineering is a powerful tool for designing or modifying therapeutic proteins for enhanced efficacy, increased safety, reduced immunogenicity, and improved delivery. Fusion proteins are an important group of therapeutic compounds that often require an ideal linker to combine diverse domains to fulfill the desired function. GGGGS [(G4S)n] linkers are commonly used during the engineering of proteins because of their flexibility and resistance to proteases. However, unexpected truncation was observed in the linker of a bispecific antibody, which presented challenges in terms of production and quality. In this work, a bispecific antibody containing 5*G4S was investigated, and the truncation position of the linkers was confirmed. Our investigation revealed that codon optimization, which can overcome the negative influence of a high repetition rate and high GC content in the (G4S)n linker, may reduce the truncation rate from 5-10% to 1-5%. Moreover, the probability of truncation when a shortened 3* or 4*G4S linker was used was much lower than that when a 5*G4S linker was used in mammalian cells. In the case of expressing a bispecific antibody, the bioactivity and purity of the product containing a shorter G4S linker were further investigated and are discussed.

The microalgal-bacterial granular sludge (MBGS) process is attracting attention as a green wastewater treatment technology. However, research on the application of MBGS in lake water remediation is limited. Thus, this experiment investigated the feasibility and the efficacy of the MBGS process for the treatment of natural lake water in a continuous-flow tubular reactor. The average removal efficiencies of COD, NH₄⁺-N, NO₃^--N, NO₂^--N, TN, PO₄^3--P, TP, and turbidity by MBGS system in the day/night cycles were 50.10/61.39%, 63.52/75.23%, 43.37/73.57%, 90.72/93.48%, 78.30/80.02%, 71.13/74.62%, 65.08/70.57%, 92.32/89.84%, respectively. As the experiment progressed, the total chlorophyll content in MBGS decreased as the granule size increased, while the extracellular polymeric substances content increased, suggesting that the lake water contributed to bacterial growth and favored the stability of MBGS. Moreover, the eukaryotic microorganisms were dominated by Chlorophyta and Rotifera, and prokaryotic microorganisms were dominated by Proteobacteria in MBGS. By promoting the decomposition of various organic compounds in the lake water and inhibiting sludge expansion, these microorganisms help the MBGS system to maintain excellent granular characteristics and performance. Overall, the MBGS system proved to be a feasible option for the remediation of natural lake waters.

Due to the prevalence of drug-resistant bacteria and the ongoing shortage of novel antibiotics as well as the challenge of treating breast cancer, the therapeutic and clinical sectors are consistently seeking effective nanomedicines. The incorporation of metal oxide nanoparticles with biological macromolecules and an organic compound emerges as a promising strategy to enhance breast cancer treatment and antibacterial activity against drug-resistant bacteria in various biomedical applications. This study aims to synthesize a unique nanocomposite consisting of CeO₂ embedded with folic acid and carboxymethyl cellulose (CFC NC) via a green precipitation method using Moringa oleifera. Various spectroscopic and microscopic analyses are utilized to decipher the physicochemical characteristics of CFC NC and active phytocompounds of Moringa oleifera. Antibacterial study against MRSA (Methicillin-resistant Staphylococcus aureus) demonstrated a higher activity (95.6%) for CFC NC compared to its counterparts. The impact is attributed to reactive oxygen species (ROS), which induces a strong photo-oxidative stress, leading to the destruction of bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CFC NC are determined as 600 µg/mL and 1000 µg/mL, respectively. The anticancer activity against breast cancer cell resulted in the IC₅₀ concentration of 10.8 μg/mL and 8.2 μg/mL for CeO₂ and CFC NC respectively.The biocompatibility test was conducted against fibroblast cells and found 85% of the cells viable, with less toxicity. Therefore, the newly synthesized CFC NC has potential applications in healthcare and industry, enhancing human health conditions.

This century has seen the rise of antibiotic resistance as a significant public health problem. In addition, oxidative stress may also be a factor in selecting resistant strains of bacteria. The current study analyzed microbially produced hyaluronic acid's antibacterial activity and antioxidant activity. It had significant antibacterial action against strains of Staphylococcus aureus and Escherichia coli, with the IC₅₀ value obtained being 487.65 µg mL^-1 for antioxidant assay. Our molecular docking investigations of hyaluronic acid on tyrosyl-tRNA synthetase (Staphylococcus aureus: -6.13 kcal/mol, Escherichia coli: -5.79 kcal/mol) and topoisomerase II DNA gyrase (Staphylococcus aureus: -5.02 kcal/mol, Escherichia coli: -4.90 kcal/mol) confirmed the ligands' possible binding mode to the appropriate targets' sites. We also employed molecular dynamics simulation and showed that HA binds more strongly with 1JIL (-85.455 ± 12.623 kJ/mol) compared to 2YXN (-49.907 ± 64.191 kJ/mol), 5CDP (-47.285 ± 13.925 kJ/mol), and 6RKS (-45.306 ± 21.338 kJ/mol). We also report that the ligand forms several hydrogen bonds in molecular simulation, implying regular interaction with key residues of the enzymes. The results in this study indicate the potential use of HA in the vast field of applications having both asthetic and medicinal values.

The effects of dilute acid prehydrolysate from poplar were investigated and compared in the enzymatic hydrolysis, fermentation, and simultaneous saccharification fermentation (SSF) in this study. The improvement of enzymatic hydrolysis and fermentation with resin adsorption and surfactant addition has also been represented. A total of 16 phenolic alcohols, aldehydes, acids and 3 furan derivatives in the prehydrolysates were identified and quantified by gas chromatography/mass spectrometry (GC/MS). The degree of inhibition from the phenolic compounds (26.55%) in prehydrolysate on the enzymatic hydrolysis was much higher than carbohydrates-derived inhibitors (0.52-4.64%). Around 40% degree of inhibition was eliminated in Avicel enzymatic hydrolysis when 75% of prehydrolysates phenolic compounds were removed by resin adsorption. This showed distinguishing inhibition degrees of various prehydrolysate phenolic compounds. Inhibition of prehydrolysate on enzymatic hydrolysis was more dosage-dependent, while their suppression on the fermentation showed a more complicated mode: fermentation could be terminated by the untreated prehydrolysate, while a small number of prehydrolysate inhibitors even improved the glucose consumption and ethanol production in the fermentation. Correlated with this distinct inhibition modes of prehydrolysate, the improvement of Tween 80 addition in SSF was around 7.10% for the final ethanol yield when the glucose accumulation was promoted by 76.6%.

Lipase is one of the most widely studied and applied biocatalysts. Due to the high enzyme leakage rate of the immobilization method of physical adsorption, we propose a new lipase immobilization method, based on the combination of macroporous resin adsorption and organic polymer coating. The immobilized Candida antarctica lipase B (CALB@resin-CAB) was prepared by combining the macroporous resin adsorption with cellulose acetate butyrate coating, and its structure was characterized by various analytic methods. Immobilized lipase was applied for biodiesel production using acidified palm oil as the starting material, the conversion rate achieved as high as 98.5% in two steps. Furthermore, the immobilized lipase displayed satisfactory stability and reusability in biodiesel production. When the aforementioned reaction was carried out in a continuous flow packed bed system, the yield of biodiesel was 94.8% and space-time yield was 2.88 g/(mL∙h). The immobilized lipase CALB@resin-CAB showed high catalytic activity and stability, which has good potential for industrial application in the field of oil processing.

Freshwater microalga Haematococcus lacustris rich in astaxanthin, as a supplemental live diet can directly supply natural astaxanthin to the aquaculture organisms, except marine aquaculture organisms, since H. lacustris cannot tolerate seawater salinity. The objective of the present study is to provide a salinity acclimation method that allows H. lacustris to survive and accumulate astaxanthin with the aim of developing a novel supplemental live diet for marine aquaculture organisms. H. lacustris cultured in freshwater was subjected to different stepwise salinity acclimation processes (two-, three-, and four-shift). As the controls, H. lacustris was exposed to five constant salinities conditions (0, 0.05, 0.075, 0.3, and 0.6 M NaCl, respectively). Among the controls, almost all cells in the 0.3 M and 0.6 M NaCl conditions died immediately. In contrast, H. lacustris in the stepwise salinity acclimation processes survived in 0.6 M NaCl (equivalent to seawater salinity of 35 psu), showing the highest living-cell proportion (50.0%) and astaxanthin yield (0.72 mg·L^-1) in the four-shift. The present study first demonstrated that H. lacustris tolerated seawater salinity through a stepwise acclimation process, proving a new strategy to supply live microalgal diets rich in natural astaxanthin for marine aquaculture.

For the first time is reported the comparison of solid biocatalysts derived from Candida rugosa lipase (CRL) immobilized on different lignocellulosic wastes (rice husk, brewer's spent grain, hemp tea waste, green tea waste, vine bark, and spent coffee grounds) focusing on the characterization of these materials and their impact on the lipase-support interaction. The wastes were subjected to meticulous characterization by ATR-FTIR, BET, and SEM analysis, besides lignin content and hydrophobicity determination. Investigating parameters influencing immobilization performance revealed the importance of morphology, textural properties, and hydrophobic interactions revealed the importance of morphology, textural properties and especially hydrophobic interactions which resulted in positive correlations between surface hydrophobicity and lipase immobilization efficiency. Hemp tea waste and spent coffee grounds demonstrated superior immobilization performances (7.20 U/g and 8.74 U/g immobilized activity, 102.3% and 33.5% efficiency, 13.4% and 15.4% recovery, respectively). Moreover, they demonstrated good temporal stability (100% and 92% residual activity after 120 days, respectively) and retained 100% of their immobilized activity after five reuses in the hydrolysis of p-nitrophenyl palmitate in hexane. In addition, the study of enzymatic desorption caused by ionic strength and detergent treatments indicated mixed hydrophobic and electrostatic interactions in rice husk, vine bark, and spent coffee grounds supports, while hemp tea waste and green tea waste were dominated by hydrophobic interactions.

The plastisphere is the microbial communities that grow on the surface of plastic debris, often used interchangeably with plastic biofilm or biofouled plastics. It can affect the properties of the plastic debris in multiple ways. This review aims to present the effects of the plastisphere on the physicochemical properties of microplastics systematically. It highlights that the plastisphere modifies the buoyancy and movement of microplastics by increasing their density, causing them to sink and settle out. Smaller and film microplastics are likely to settle sooner because of larger surface areas and higher rates of biofouling. Biofouled microplastics may show an oscillating movement in waterbodies when settling due to diurnal and seasonal changes in the growth of the plastisphere until they come close to the bottom of the waterbodies and are entrapped by sediments. The plastisphere enhances the adsorption of microplastics for metals and organic pollutants and shifts the adsorption mechanism from intraparticle diffusion to film diffusion. The plastisphere also increases surface roughness, reduces the pore size, and alters the overall charge of microplastics. Charge alteration is primarily attributed to changes in the functional groups on microplastic surfaces. The plastisphere introduces carbonyl, amine, amide, hydroxyl, and phosphoryl groups to microplastics, causing an increase in their surface hydrophilicity, which could alter their adsorption behaviors for heavy metals. The plastisphere may act as a reactive barrier that enhances the leaching of polar additives. It may anchor bacteria that can break down plastic additives, resulting in decreased crystallinity of microplastics. This review contributes to a better understanding of how the plastisphere alters the fate, transport, and environmental impacts of microplastics. It points to the possibility of engineering the plastisphere to improve microplastic biodegradation.